GEOSCAN, résultats de la recherche


TitreVariation in evolutionary patterns across the geographic range of a fossil bivalve
AuteurGrey, M; Haggart, J W; Smith, P L
SourceScience vol. 322, 2008 p. 1238-1241,
Séries alt.Secteur des sciences de la Terre, Contribution externe 20080418
ÉditeurAmerican Association for the Advancement of Science (AAAS)
Documentpublication en série
Mediapapier; en ligne; numérique
Sujetsdistribution de fossiles; fossiles; assemblages fossiles; distribution géographique des fossiles; zones fossilifères; descriptions des fossiles; morphologie des fossiles; évolution; milieux marins; milieu sédimentaire; Buchie; paléontologie; Mésozoïque
Illustrationstables; plots; stratigraphic columns; drawings; histograms
Résumé(disponible en anglais seulement)
The fossil record is the only direct source of data for studying modes (patterns) and rates of morphological change over evolutionary time periods. Determining modes and rates is important for understanding macroevolutionary processes, but just how modes and rates can vary within a taxon, and why, remain largely unaddressed. We examined patterns of morphological change in the shell of the Mesozoic marine bivalve genus Buchia over its geographic and temporal range. Modes conform to either random walks or stasis and both modes and rates show variability between locations. For example, stasis is more commonly noted in deeper marine environments while random walks occur more often at the highest paleolatitudes studied. These results indicate that the environment can play a significant role in shaping patterns of evolution.